Abstract: A method for MIP mapping index texture. This invention has index texture with texel index values which refer to physical material properties. First, a lookup table is stored and the lookup table has table entries defining material types. Each table entry has an index, and material property type values. Then at least two texels are selected from the index texture, where each texel has index values corresponding to table entries. Next, the material property type values are averaged for each separate property type from the table entries for the selected texels. This produces an average material property value for each material property type. Another step is selecting a new material index based on the material which most closely matches the average material property values. The final step is generating the next lowest MIP level by using the new material indexes to form a new index texture with fewer texels.

Abstract: A method and apparatus for accessing a cache memory of a computer graphics system, the apparatus including a frame buffer memory having a graphics memory for storing pixel data for ultimate supply to a video display device, a read cache memory for storing data received from the graphics memory, and a write cache memory for storing data received externally of the frame buffer and data that is to be written into the graphics memory. Also included is a frame buffer controller for controlling access to the graphics memory and read and write cache memories. The frame buffer controller includes a cache first in, first out (FIFO) memory pipeline for temporarily storing pixel data prior to supply thereof to the cache memories.

Abstract: A method for anticipation and tracking eye movement for head tracked projectors which divides a projection surface into spherical triangles and uses interpolating calibration values stored at each vertex of the triangle. A calibration map is used that contains information about the relationship between the user's head orientation and where they are looking with their eyes at each calibration point. The projection surface is divided into spherical triangles which are searched to find the triangle which contain the user's interpolated view point by performing a dot product test between the interpolated view point and the unit normal vectors inside the three planes that make up the sides of the spherical triangle extended back to the eye point. When a dot product test fails for any side of the triangle the pointer is followed to the adjacent triangle where the test starts over.

Abstract: A method for creating a span-based multisample Z-buffer pixel processor in a computer graphics system to thereby reduce a quantity of data that must be stored for each pixel in a frame buffer thereof. By taking advantage of areal coherence, the quantity of data that must be stored in each pixel is reduced. By employing merging, the method is also able to ensure than pixel storage requirements do not grow beyond a predetermined limit.

Abstract: This invention relates generally to the field of computer graphics display, and more particularly to reducing the amount of time needed to render complex virtual scenes on a computer graphics display. This invention combines the advantages of the prior art methods of list priority and depth buffering (e.g. Z-buffering) with new simplified and enhanced full buffer processes. In one embodiment, a simplified full buffer arrangement enables the elimination of rendering primitives prior to pixel shading for regions of the screen which have previously been covered by closer primitives. Another embodiment provides for an enhanced full buffer that combines the coverage of a previously rendered primitive in a partial buffer and associates it with a current primitive to cover pixel arrays.

Abstract: A geometric processor provides object primitives, as triangles, in graphic display image space to support a dynamic display. The image space is defined by pixels, in turn specified in arrays as spans. In a multi-level scanning operation, primitives are scanned at a first level to locate lapped spans that are lapped by primitives. At a second level, spans are scanned to process pixels that are lapped by primitives. An alternative embodiment discloses three-level scanning in association with parallel pixel processing. Concurrent texturing structure operates along with cache memories.

Abstract: A method for rendering large-area time-based shadows. A first step is to pre-process a database of three dimensional constructs that define all primitives and attributes of the primitives in a three dimensional simulated environment. The pre-processing step determines the time relevant behavior of the shadows by calculating an angle at which the primitive is illuminated, and an angle at which illumination ceases. The second step is to process the database at run-time using the pre-processed database of three dimensional constructs and pre-calculated illumination and no-illumination angles.

Abstract: A method and an apparatus for improved pixel shading. The method of the present invention is based upon the notion of allowing multiple polygons to contribute to the net transmittance effect of a single pixel. This is accomplished by providing a new multi-sample data structure which can store visual attributes for each polygon, sorting all the transparent polygons in a front-to-back arrangement, processing the transparent polygon records and then the opaque polygon records by accumulating the net effect of the transmittance of all polygons being sampled in a pixel, and applying the color attributes to the net effect of transmittance, thereby decoupling color from the calculations for determining transmittance.

Abstract: A method for creating a large-scale synthetic environment simulation which can be used in real-time. The method enables real-time viewing, control and interaction of automatically generated, abstract feature models and terrain surface models having multiple levels of detail, while providing correlated multi-sensor viewing and interaction of objects.

Abstract: Disclosed is a golf ball designed for longer travel relative the compression of the ball. The golf ball includes: (1) a flexible inner core, preferably comprised of crosslinked synthetic rubber, (2) a perforated barrier shell positioned outside of, and surrounding, the inner core to lessen deformation of the ball when the ball is struck by a golf club, (3) a flexible outer core, preferably comprised of crosslinked, synthetic rubber or windings, positioned outside of and surrounding the perforated barrier shell, and (4) an outer cover, preferably comprised of ionomeric resin material, positioned outside of and surrounding the outer core. The perforated barrier shell reduces deformation of the golf ball upon impact by a golf club and is preferably formed as a sphere centered in the golf ball, preferably having a diameter equal to one-half the diameter of the golf ball.

Abstract: A method and apparatus for rendering a real-time synthetic environment on a computer display. A hidden surface removal technique is provided which combines an efficient pixel rendering architecture with a simplified modeling process. Specifically, the computer pixel graphics hardware processing load is balanced against a software geometric load to obtain optimum rendering performance by utilizing a "full" buffer in combination with adaptations of the z-Buffer and priority-list algorithms.

Abstract: A new method and apparatus for creating, positioning and manipulating a garbage matte which obscures everything outside of a three-dimensional physical set or blue stage. Effectively, the garbage matte is a "negative" of a blue stage. What is important is that the garbage matte is created either as a virtual enclosure around all virtual objects in the virtual environment, or simply as a background color of the graphics engine generating the garbage matte. In this way, the garbage matte provides extensions of blue screens which comprise the blue stage, extending all the way around and behind the television cameras. Consequently, a compositor will not include in a composited output image those physical set elements which are masked by the virtual garbage matte. The compositor will replace areas hidden by the garbage matte with image data supplied by the computer image generator which stores the virtual environment.

Abstract: A method and apparatus for producing data in a virtual set memory representing a composite image. The composite image data is produced from a combination of data representing a virtual image and data representing a camera field of view image. The invention includes a plurality of cameras, each disposed for developing data representing a respective field of view and each having a still store frame buffer associated therewith for receiving and storing data representing virtual images. The still store frame buffers are configured for subsequent selective retrieval. The invention also includes a virtual image data source for generating data representing virtual images and for supplying such data to the still store frame buffers associated with each of the plurality of cameras.